Misc. Technology - II Silicon Wafer, Vacuum Tube Pluggable Unit, 2860 Channel Panel
This is a page of more-or-less random technology pictures. Click on the small version to see a larger version. Following is an entire backplane of circuit boards from an IBM 2501 card reader. Dated tags say 1967. The alum cans are Solid Logic Technology (SLT). See picture of a 2501 below. Following is an entire circuit backplane from an IBM 3420 tape drive. This is back when a tape drive stood 5-6 feet tall and weighed 300 lbs. The alum cans are Monolithic Systems Technology (MST). See picture of 3420 tape drives. Below is the button panel from a 2501 card reader and a complete 2501. How are punch cards made? Below is a set of two punch card printing drums. Visit the Project: Make New Punch Cards page to make some cards. Perhaps these are the first new cards from these drums in more than 30 years! Below is a carriage tape punch and an IBM hex key. The punch was used to punch holes in paper tape which was then installed and used as a kind of formatting instruction recipe in printing equipment such as the 1403 printer. The hex key was useful for opening cabinets and also happened to be the right size to remove hex bolts holding in SLT backplanes (see SLT and MST backplanes above). Before electronically stored program computers, computing devices stored programs on plug boards. To program the device, wires were inserted and connected between holes. The device interpreted these connections as instructions. Below is an example plug board with a bit of rats nest wiring. Test Devices The Gallery has a small collection of devices built especially for testing. Here are a few of them. Below is the Maintanence Device 1, made in 1980. It came with lots of cables, various plugs, and a handheld keypad with LED display. It has an integrated 8" floppy drive to load diagnostic programs for the various things this little Doctor-in-a-Briefcase could diagnose (3880 disk control units, 3480 tape drives, 8100 distributed computing system). Apparently this device could also diagnose the 3082 (can anyone confirm this?), which was the service processor for 308X computer complexes (processor models 3081, 3083, 3084). MD-1 really is a mini-computer in a briefcase using an IBM UC-0 processor. Apparently the 8" floppy design wasn't ideal -- if you accidently closed the unit with a diskette in the drive, the disk and possibly the drive would be damaged. Does anyone still have any program listings for MD-1? Thanks to John Atkinson and Martin Brown for additional information on MD-1. Below is an unidentified testing device. It is very heavy and had two large fat cables coming out the back. Inside is a complete backplane populated with circuit cards, so it obviously has some sophisticated logic capabilities. There are no tags on the outside identifying a model or type. Some of the labels on the front include: Probe Input, Signal Lines to Device Adapters, Sample INTLK, Set Control, Hold Control, Reset, Console Display. There is a manufacturing, or service upgrade tag inside that says 1969. The device matches IBM System 360 (color, light style, SLT circuits, vintage). It may have been designed to diagnose communications equipment for System 360 or a peer architecture from the 1960's. Any help identifying this will be appreciated. Many have tried! Below is a hand-held 3420 tape unit tester. See picture of 3420 tape drives. Below is a test device predating the 3420 tape drives. This device has a variety of overlays so that the lights can indicate different things for different devices. Overlays with this device include 2501 Card Reader, 2844, 2314, 1442, and 2701. This device also still has its original schematics in a plastic sleeve inside and a dated tag from 1965. Pictured below is a special purpose testing card. Cards like this were designed to plug in to standard System 360 slotted backplanes and "sniff." This card was used by customer engineers (CEs) to read fault codes in 3203 line printers (the switch is to reset the card). Below is a Tektronix 310 oscilloscope, which had a 1956 list price of $595. (the 2006 equivalent is about $4300.). The front panel was silkscreened with the IBM logo and so was manufactured specifically for IBM. Hopefully it has no special circuitry -- the Gallery has located a generic Tek 310 service manual and will restore the device to running condition. To the right in the photo is a System 360 backplane of SLT (Solid Logic Technology) circuit boards. Return to The Gallery of Old Iron home page

Misc. Technology - II

Silicon Wafer, Vacuum Tube Pluggable Unit, 2860 Channel Panel

This is a page of more-or-less random technology pictures. Click on the small version to see a larger version.

Following is an entire backplane of circuit boards from an IBM 2501 card reader. Dated tags say 1967. The alum cans are Solid Logic Technology (SLT). See picture of a 2501 below.

Following is an entire circuit backplane from an IBM 3420 tape drive. This is back when a tape drive stood 5-6 feet tall and weighed 300 lbs. The alum cans are Monolithic Systems Technology (MST). See picture of 3420 tape drives.

Below is the button panel from a 2501 card reader and a complete 2501.

How are punch cards made? Below is a set of two punch card printing drums. Visit the Project: Make New Punch Cards page to make some cards. Perhaps these are the first new cards from these drums in more than 30 years!

Below is a carriage tape punch and an IBM hex key. The punch was used to punch holes in paper tape which was then installed and used as a kind of formatting instruction recipe in printing equipment such as the 1403 printer. The hex key was useful for opening cabinets and also happened to be the right size to remove hex bolts holding in SLT backplanes (see SLT and MST backplanes above).

Before electronically stored program computers, computing devices stored programs on plug boards. To program the device, wires were inserted and connected between holes. The device interpreted these connections as instructions. Below is an example plug board with a bit of rats nest wiring.

Test Devices

The Gallery has a small collection of devices built especially for testing. Here are a few of them.

Below is the Maintanence Device 1, made in 1980. It came with lots of cables, various plugs, and a handheld keypad with LED display. It has an integrated 8" floppy drive to load diagnostic programs for the various things this little Doctor-in-a-Briefcase could diagnose (3880 disk control units, 3480 tape drives, 8100 distributed computing system). Apparently this device could also diagnose the 3082 (can anyone confirm this?), which was the service processor for 308X computer complexes (processor models 3081, 3083, 3084).

MD-1 really is a mini-computer in a briefcase using an IBM UC-0 processor. Apparently the 8" floppy design wasn't ideal -- if you accidently closed the unit with a diskette in the drive, the disk and possibly the drive would be damaged. Does anyone still have any program listings for MD-1?

Thanks to John Atkinson and Martin Brown for additional information on MD-1.

Below is an unidentified testing device. It is very heavy and had two large fat cables coming out the back. Inside is a complete backplane populated with circuit cards, so it obviously has some sophisticated logic capabilities. There are no tags on the outside identifying a model or type. Some of the labels on the front include: Probe Input, Signal Lines to Device Adapters, Sample INTLK, Set Control, Hold Control, Reset, Console Display. There is a manufacturing, or service upgrade tag inside that says 1969. The device matches IBM System 360 (color, light style, SLT circuits, vintage). It may have been designed to diagnose communications equipment for System 360 or a peer architecture from the 1960's.

Any help identifying this will be appreciated. Many have tried!

Below is a hand-held 3420 tape unit tester. See picture of 3420 tape drives.

Below is a test device predating the 3420 tape drives. This device has a variety of overlays so that the lights can indicate different things for different devices. Overlays with this device include 2501 Card Reader, 2844, 2314, 1442, and 2701. This device also still has its original schematics in a plastic sleeve inside and a dated tag from 1965.

Pictured below is a special purpose testing card. Cards like this were designed to plug in to standard System 360 slotted backplanes and "sniff." This card was used by customer engineers (CEs) to read fault codes in 3203 line printers (the switch is to reset the card).

Below is a Tektronix 310 oscilloscope, which had a 1956 list price of $595. (the 2006 equivalent is about $4300.). The front panel was silkscreened with the IBM logo and so was manufactured specifically for IBM. Hopefully it has no special circuitry -- the Gallery has located a generic Tek 310 service manual and will restore the device to running condition. To the right in the photo is a System 360 backplane of SLT (Solid Logic Technology) circuit boards.

Return to The Gallery of Old Iron home page